Battery packs having structural members for improving thermal management

ABSTRACT

Battery packs are presented having structural members for improving thermal management of battery cells therein. In some embodiments, the battery packs include a first end-member positioned opposite a second end-member and parallel thereto. The battery packs also include a first side beam positioned opposite a second side beam and parallel thereto. The first side beam and the second side beam extend longitudinally between the first end-member and the second end-member. A longitudinal member is disposed between the first side beam and the second side beam and defines a plurality of longitudinal rows. The battery packs may additionally include a lateral member disposed between first end-member and the second end-member to partition the plurality of longitudinal rows into an array of battery cell compartments. A battery cell is disposed within at least one battery cell compartment.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.17/657,914, filed Apr. 4, 2022, which is a continuation of U.S. patentapplication Ser. No. 16/259,440, filed Jan. 28, 2019, which is acontinuation of International Patent Application Serial No.PCT/US2017/044316, filed Jul. 28, 2017, which claims the benefit of U.S.Patent Application Ser. No. 62/368,779, filed Jul. 29, 2016, thedisclosures of which are hereby incorporated by reference in theirentirety for all purposes.

FIELD

This disclosure relates generally to battery packs.

BACKGROUND

In some designs, battery cells are packaged in groups (called packs) toaggregate overall storage of electrical energy. A battery pack includesa structure that houses or otherwise holds together constituent batterycells. Battery pack design may involve compromises. For example,packaging battery cells closely increases overall energy density, whichis beneficial, but may also increase heat transfer between batterycells, which may not be beneficial, at temperature extremes.

SUMMARY

In some embodiments, a battery pack for packaging an array of batterycells includes a first end-member positioned opposite a secondend-member and parallel thereto. The battery pack also includes a firstside beam positioned opposite a second side beam and parallel thereto.The first side beam and the second side beam extend longitudinallybetween the first end-member and the second end-member. A longitudinalmember is disposed between the first side beam and the second side beamand defines a plurality of longitudinal rows. The battery packadditionally includes a lateral member disposed between the firstend-member and the second end-member to partition the plurality oflongitudinal rows into an array of battery cell compartments. A batterycell is disposed within at least one battery cell compartment. At leastone of the longitudinal member, the first side beam, and the second sidebeam are configured to be in tension when the array of battery cellcompartments contains a longitudinal row of battery cells extending fromthe first end-member to the second end-member.

In some instances, the battery cell includes an aluminum can. In otherinstances, the battery cell includes a steel can.

In some instances, the battery pack includes a jacket enclosing one ormore battery cells disposed within each battery cell compartment andhaving apertures configured to expose terminals of the one or morebattery cells. In some instances, the battery pack includes a sleevecovering one or more battery cells disposed within each battery cellcompartment and having a first portion and a second portion. The firstportion covers the battery cells along first sides having terminalsdisposed therein, or covers the battery cells along first sides oppositesides having terminals disposed therein. The first portion may haveapertures configured to expose terminals of the battery cells. Thesecond portion covers second sides of the battery cells. The secondsides are adjacent the first sides. In some instances, the battery packincludes a base panel having openings configured to expose cell vents ofthe battery cell. The battery pack also includes a cover panel havingapertures configured to expose terminals of the battery cell. In theseinstances, the longitudinal member divides the lateral member, the firstend-member, and the second end-member into separate portions.

In other embodiments, a battery pack includes a tubular structure. Thetubular structure includes a base member having a bottom wall extendingfrom a first side wall to a second side wall. The tubular structure alsoincludes a cover member coupled to the base member to define a channeltherebetween. The cover member has apertures configured to exposeterminals of the battery cells. The tubular structure additionallyincludes a lateral member disposed within the channel to divide thechannel into a plurality of battery cell compartments. A firstend-member is disposed at a first end of the channel. A secondend-member is disposed at a second end of the channel. At least one ofthe base member and the cover member are configured to be in tensionwhen the plurality of battery cell compartments contains a row ofbattery cells extending from the first end-member to the secondend-member. The battery pack also includes a battery cell disposedwithin at least one battery cell compartment.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be readily understood by the following detaileddescription in conjunction with the accompanying drawings, wherein likereference numerals designate like structural elements, and in which:

FIG. 1A is a perspective view of a battery pack for packaging an arrayof battery cells within structural members that provide thermalmanagement, according to an illustrative embodiment;

FIG. 1B is an exploded view of the battery pack of FIG. 1A;

FIG. 2A is a perspective view of a battery pack having structuralmembers that provide thermal management, according to an illustrativeembodiment;

FIG. 2B is an exploded view of the battery pack of FIG. 2A;

FIG. 2C is an exploded view of a battery pack according to illustrativeembodiments;

FIG. 2D is an exploded view of the battery pack of FIG. 2A, but in whichjackets enclose the battery cells, according to an illustrativeembodiment;

FIG. 2E is an exploded view of the battery pack of FIG. 2A, but in whichsleeves cover the battery cells, according to an illustrativeembodiment;

FIG. 2F is an exploded view of the battery pack of FIG. 2A, but in whichthe longitudinal member defines tubular structures within the batterypack, according to an illustrative embodiment;

FIG. 3A is a perspective view of a battery pack having structuralmembers that provide thermal management, according to anotherillustrative embodiment; and

FIG. 3B is an exploded view of the battery pack of FIG. 3A.

DETAILED DESCRIPTION

Reference will now be made in detail to representative embodimentsillustrated in the accompanying drawings. It should be understood thatthe following descriptions are not intended to limit the embodiments toone preferred embodiment. To the contrary, it is intended to coveralternatives, modifications, and equivalents as can be included withinthe spirit and scope of the described embodiments as defined by theappended claims.

The embodiments described herein are directed to structures for housingmultiple battery cells, i.e., for forming a battery pack. The batterypacks may include structural members that serve multiple functions, suchas load-bearing, thermal-management, confinement, battery compression,and so forth.

In some embodiments, the structural members improve a stiffness of thebattery packs to vertical loads while improving thermal management amonga plurality (e.g., array) of battery cell compartments. Such thermalmanagement includes managing heat flow between neighboring batterycells, and in some instances assists a flow of thermal energy out of thebattery cells. In another aspect, the structural members are configuredto pack the battery cells in a space-efficient arrangement. Thisspace-efficient arrangement increases a volume allocated to storingelectrical energy. In yet another aspect, the structural memberscompress the battery cells when disposed within the plurality of batterycell compartments. Such compression may reduce swelling of the batterycells during operation (e.g., charging, discharging, etc.). Reducedswelling may improve performance, lifetime, or both, of the batterycells.

As used herein, the term “thermal management” refers to a regulation ofthermal energy flowing into and out of one or more battery cells withina battery pack. The term “thermal management” may also refer to acontrol or confinement of thermally-induced chemical reactions (andtheir by-products) that result from electrochemical processes withinbattery cells.

Now referring to FIG. 1A, a perspective view is presented of a batterypack 100 for packaging an array of battery cells 102 within structuralmembers that provide thermal management, according to an illustrativeembodiment. FIG. 1B provides an exploded view of the battery pack 100illustrated in FIG. 1A. The battery pack 100 includes a first end-member104 positioned opposite a second end-member 106 and parallel thereto.The first end-member 104 and the second end-member 106 may be disposednormal to a longitudinal axis 108 of the battery pack 100. The firstend-member 104 and the second end-member 106 are operable to applypressure longitudinally against the array of battery cells 102 withinthe battery pack 100. In some embodiments, the first end-member 104, thesecond end-member 106, or both include plate structures.

The battery pack 100 also includes a first side beam 110 positionedopposite a second side beam 112 and parallel thereto. The first sidebeam 110 and the second side beam 112 may be disposed normal to alateral axis 114 of the battery pack 100. The first side beam 110 andthe second side beam 112 extend longitudinally between the firstend-member 104 and the second end-member 106. Such extension may definea perimeter 116 (see dashed line in FIG. 1A) with the first end-member104 and the second end-member 106. Exemplary pack 100 has perimeter 116that is rectangular. In some embodiments, the first side beam 110 andthe second side beam 112 apply pressure laterally against the array ofbattery cells 102 within the battery pack 100.

The first side beam 110 and the second side beam 112 may be coupled tothe first end-member 104 and the second end-member 106 via welds,brazes, adhesives (e.g. epoxies, cements, etc.), fasteners (e.g., bolts,rivets, etc.), or some combination thereof. Moreover, cross-sections forthe first side beam 110 and the second side beam 112 may vary dependingon requirements for stiffness and weight. Non-limiting examples ofcross-sections include I-beams, T-beams, C-channels, L-beams, solidsquares, hollow squares, solid rectangles, hollow rectangles, solidrounds, and hollow rounds. Other cross-sections are possible.

Turning to FIG. 1B, battery pack 100 in some embodiments includes alongitudinal member 118 disposed between the first side beam 110 and thesecond side beam 112 and defining a plurality of longitudinal rows. Thelongitudinal member 118 may be formed using multiple components, asshown in FIGS. 1A and 1B. In some embodiments, the longitudinal member118 includes two straps 120, each having a first end (not shown) and asecond end 122 coupled to, respectively, the first endplate 104 and thesecond endplate 106.

Although a single longitudinal member 118 is depicted in FIGS. 1A and1B, this depiction is not intended as limiting. Any number oflongitudinal members 118 is possible for the battery pack 100 (i.e., thebattery pack 100 includes a plurality of longitudinal members 118). Insome instances, the longitudinal member 118 is disposed between thefirst side beam 110 and the second side beam 112 such that the pluralityof longitudinal rows have equal widths. In other instances, thelongitudinal member 118 is disposed between the first side beam 110 andthe second side beam 112 such that the plurality of longitudinal rowshave different widths. In general, a position of the longitudinal member118 may be selected to set a width of one or more longitudinal rowswithin the battery pack 100. Non-limiting examples of the longitudinalmember 118 include sheets, plates, and slats. Other types oflongitudinal members 118 are possible.

The battery pack 100 also includes a lateral member 124 disposed betweenthe first end-member 104 and the second end-member 106 to partition theplurality of longitudinal rows into an array of battery cellcompartments. The lateral member 124 may be formed using multiplecomponents. In some embodiments, such as that shown in FIGS. 1A and 1B,the battery pack 100 includes a plurality of lateral members 124.However, in some embodiments, a single lateral member 124 is possible.In general, a number and position of the lateral member 124 may beselected to determine, respectively, a number and width of one or morelateral rows within the battery pack 100.

In exemplary pack 100, lateral member(s) 124 connect to first side beam110 and second side beam 112. The lateral member 124 may have oppositeends that include a tab. One or both of the opposite ends may includethe tab. The tab may assist in coupling the lateral member 124 to thefirst side beam 110, the second side beam 112, or both. In someembodiments, the lateral member 124 includes a first tab (not shown) anda second tab 126 at opposite ends. In these embodiments, the first taband the second tab 126 protrude through slots 128 in, respectively, thefirst side beam 110 and the second side beam 112. In some embodiments,the first tab and the second tab 126 are coupled to, respectively, thefirst side beam 110 and the second side beam 112 via a fastener 130.

The lateral member 124, in combination with the longitudinal member 118,partitions a volume bounded by the first end-member 104, the secondend-member 106, the first side beam 110, and the second side beam 112into an array of battery cell compartments 132 (see solid line). Thearray of battery cell compartments 132 may correspond to an array ofrectangular volumes, such as depicted in FIGS. 1A and 1B. However, thisdepiction is not intended as limiting. Other volumetric shapes arepossible for the array of battery cell compartments 132. It will beappreciated that longitudinal members 118 and lateral members 124 may bechosen in any number and position to define any quantity and size ofbattery cell compartments 132 within the battery pack 100. By suchselection, a space-efficient packaging of battery cells 102 may beachieved within the battery pack 100. In some embodiments, battery cells102 are prismatic cells, and the packaging of battery 100 may involve noappreciable gaps between abutting battery cells.

In some embodiments, the longitudinal member 118 and the lateral member124 are formed of sheets or thin plates. Longitudinal member 118 and thelateral member 124 may allow a close packing of adjacent battery cells102. Non-limiting examples of materials for the sheets or thin platesinclude metals (e.g., aluminum, steel, etc.), ceramics (e.g., silica,alumina, etc.), glasses (e.g., borosilicate glass, amorphous carbon,etc.), composites (e.g., carbon-fiber or graphene laminates), andplastics (e.g., polyetherketones, polyphenylene sulfide, etc.). Othermaterials are possible, including combinations of materials.

In some embodiments, at least one of the longitudinal members 118, thefirst side beam 110, and the second side beam 112 are configured to bein tension when the array of battery cell compartments 132 contains alongitudinal row of battery cells 102 extending from the firstend-member 104 to the second end-member 106. In some embodiments, atleast one of the lateral member 124, the first endplate 104, and thesecond endplate 106 are configured to be in tension when the array ofbattery cell compartments 132 contains a lateral row of battery cells102 extending from the first side beam 110 to the second side beam 112.

Longitudinal tensioning predisposes the end-members 104, 106 to compressthe battery cells 102 along the longitudinal axis 108. Similarly,lateral tensioning predisposes the side beams 110, 112 to compress thebattery cells 102 along the lateral axis 114. Such compression mayreduce swelling of the battery cells 102 during operation (e.g., duringcharging, discharging, etc.). Reduced swelling may improve performance,lifetime, or both, of the array of battery cells 102. The tensioningalso holds battery cells 102 in place during movement of pack 100.

It will be appreciated that the longitudinal member 118 and the lateralmember 124 serve as “webbing” within the volume bounded by the firstend-member 104, the second end-member 106, the first side beam 110, andthe second side beam 112 (i.e., bounded by the perimeter 116.) In someembodiments, this “webbing” stiffens the battery pack 100 whilesimultaneously improving thermal management. Stiffening of the batterypack 100 improves resistance to loads, e.g., vertical loadsperpendicular to a plane defined by the longitudinal axis 108 and thelateral axis 114. This improved resistance allows the battery pack 100to incorporate longer rows of battery cells 102 (i.e., along thelongitudinal axis 108, the lateral axis 114, or both) than thoseassociated with conventional battery packs. In some embodiments,stiffness of the battery pack 100 may be modified by altering alongitudinal tension of the longitudinal member 118, the first side beam110, the second side beam 112, or any combination thereof. In someembodiments, the stiffness of the battery pack 100 may be modified byaltering lateral tension of the lateral member 124, the first end-member104, the second end-member 106, or any combination thereof.

The thermal functionality of the “webbing” is aided by acompartmentalized configuration, which helps isolate potential heatsources within controlled volumes. Such controlled volumes are boundedby walls associated with individual battery cell compartments 132. Asdiscussed below, in some examples, battery cell compartment 132 iswalled by a jacket. In some examples, battery cell compartment 132 iswalled by a sleeve. In some examples, battery cell compartment 132 iswalled by portions of the longitudinal member 118 and the lateral member124. These walls optionally include one or more insulative materials toenhance the thermal functionality. In some instances, the walls mayinclude coatings or linings of thermally-insulating material (e.g.,porous ceramics), thermally-conductive material (e.g., copper),intumescent material, or any combination thereof. In some instances, thewalls may be thermally-coupled to a heat exchanger. Thiscompartmentalized configuration increases volumetric density of batterypack 100 while allowing for proper thermal management.

The thermal functionality of the “webbing” impedes thermal energy frompropagating between neighboring battery cells 102 and/or battery cellcompartments 132. However, the “webbing” may also conduct thermal energyout of the array of battery cells 102. For example, and withoutlimitation, the “webbing” may be configured to conduct thermal energyvertically out of the array of battery cells 102. In some embodiments,such conduction is assisted by anisotropic materials lining the array ofbattery cell compartments 132 (e.g., graphene sheets coating walls ofthe array of battery cell compartments 132). Anisotropic materials mayhave a high thermal resistance along a first direction that connectsneighboring battery cells 102 and a low thermal resistance along asecond direction that is perpendicular to the first direction.

The battery cells 102 may be disposed within the battery pack 100 toyield an array of battery cells. In some embodiments, the array ofbattery cells 102 occupies greater than 84% of the volume enclosed bythe perimeter 116. In some embodiments, the array of battery cells 102occupies greater than 86% of the volume enclosed by the perimeter 116.In some embodiments, the array of battery cells 102 occupies greaterthan 88% of the volume enclosed by the perimeter 116. In someembodiments, the array of battery cells 102 occupies greater than 90% ofthe volume enclosed by the perimeter 116. In some embodiments, the arrayof battery cells 102 occupies greater than 92% of the volume enclosed bythe perimeter 116. In some embodiments, the array of battery cells 102occupies greater than 94% of the volume enclosed by the perimeter 116.In some embodiments, the array of battery cells 102 occupies greaterthan 96% of the volume enclosed by the perimeter 116. In someembodiments, the array of battery cells 102 occupies greater than 98% ofthe volume enclosed by the perimeter 116.

In some embodiments, such as that depicted in FIGS. 1A and 1B, eachbattery cell compartment 132 of the array of battery cell compartments132 is configured to contain two battery cells 102 therein. However,this depiction is not intended as limiting. Other numbers of batterycells 102 may be contained within each battery cell compartment 132,including differing numbers of battery cells 102 within differingbattery cell compartments. In some embodiments, the array of batterycell compartments 132 is configured such that battery cells 102 disposedtherein have terminals 134 aligned parallel to the lateral member 124.

Materials for components of the battery pack 100 may be selected bythose skilled in the art based on considerations of yield strength,elastic modulus, thermal conductivity, and melting point. Otherconsiderations are possible.

In some embodiments, at least one of the first end-member 104, thesecond end-member 106, the first side beam 110, and the second side beam112 comprise a material having a yield strength greater than 250 MPa. Insome embodiments, at least one of the first end-member 104, the secondend-member 106, the first side beam 110, and the second side beam 112comprise a material having a yield strength greater than 275 MPa. Insome embodiments, at least one of the first end-member 104, the secondend-member 106, the first side beam 110, and the second side beam 112comprise a material having a yield strength greater than 300 MPa. Insome embodiments, at least one of the first end-member 104, the secondend-member 106, the first side beam 110, and the second side beam 112comprise a material having a yield strength greater than 325 MPa. Insome embodiments, at least one of the first end-member 104, the secondend-member 106, the first side beam 110, and the second side beam 112comprise a material having a yield strength greater than 350 MPa. Insome embodiments, at least one of the first end-member 104, the secondend-member 106, the first side beam 110, and the second side beam 112comprise a material having a yield strength greater than 375 MPa.

In some embodiments, at least one of the first end-member 104, thesecond end-member 106, the first side beam 110, and the second side beam112 comprise a material having an elastic modulus greater than 65 GPa.In some embodiments, at least one of the first end-member 104, thesecond end-member 106, the first side beam 110, and the second side beam112 comprise a material having an elastic modulus greater than 80 GPa.In some embodiments, at least one of the first end-member 104, thesecond end-member 106, the first side beam 110, and the second side beam112 comprise a material having an elastic modulus greater than 95 GPa.In some embodiments, at least one of the first end-member 104, thesecond end-member 106, the first side beam 110, and the second side beam112 comprise a material having an elastic modulus greater than 110 GPa.

In some embodiments, at least one of the first end-member 104, thesecond end-member 106, the first side beam 110, and the second side beam112 comprise aluminum or an aluminum alloy (e.g., 2024, 6061, 7075,etc.). In other embodiments, at least one of the first end-member 104,the second end-member 106, the first side beam 110, and the second sidebeam 112 comprise steel (e.g., 304, 316, 1018, 4140, etc.). In stillother embodiments, at least one of the first end-member 104, the secondend-member 106, the first side beam 110, and the second side beam 112comprise titanium or a titanium alloy (e.g., Grade 1, Grade 2, Grade 5,Grade 23, etc.).

In some embodiments, the longitudinal member 118 and the lateral member124 comprise a material having a thermal conductivity greater than 10μm/m° C. In some embodiments, the longitudinal member 118 and thelateral member 124 comprise a material having a melting point greaterthan 550° C. In some embodiments, the longitudinal member 118 and thelateral member 124 comprise steel (e.g., 304, 316, 1018, 4140, etc.). Instill other embodiments, the longitudinal member 118 and the lateralmember 124 comprise titanium or a titanium alloy (e.g., Grade 1, Grade2, Grade 5, Grade 23, etc.).

In some embodiments, battery cells 202 have aluminum cans. The aluminumcan may be formed of aluminum or an aluminum alloy (e.g., 2024, 6061,7075, etc.). In other embodiments, battery cells 202 have steel cans.The steel can may be formed of any type of steel alloy (e.g., 304, 316,1018, 4140, etc.).

FIG. 2A is a perspective view of exemplary battery pack 200. FIG. 2B isan exploded view illustrating an exemplary construction of battery pack200 in accordance with some embodiments. Battery pack 200 may includesimilar components as discussed with regard to battery pack 100, and mayinclude any of the features or components previously described. Forexample, battery pack 200 as illustrated may include an array of batterycells 202 disposed in battery cell compartments 232, which may includeor contain a plurality of battery cells including at least two, at leastfour, at least six, or more battery cells 202 within each battery cellcompartment 232. The battery cell compartments 232 may be at leastpartially defined by first end-member 204, second end-member 206, firstside beam 210, and second side beam 212, which may define a perimeter216.

A longitudinal member 218 may be positioned within the battery packalong a longitudinal axis 208. Longitudinal member 218 may includestraps 220 including ends 222. Additionally, one or more lateral members224 may be positioned along a lateral axis 214. Lateral members 224 maydefine tabs 226 on either or both ends of the structure, which maycouple through slots 228 in first side beam 210 and/or second side beam212. Fasteners 230 may be used to couple tabs 226 with the associatedside beams. Battery cells 202 may have terminals 234 on a side differentthan that of a cell vent (e.g., an opposite side, adjacent side, topside, etc.). The terminals 234 may be disposed on a top side of thebattery cell 202 and the cell vent disposed on a bottom side of thebattery cell 202.

Two or more battery cells 202 are disposed within at least one batterycell compartment 232 of the array of battery cell compartments 232.Optionally, a thermal divider is disposed between adjacent battery cells202. The thermal divider may be a thermally-insulating material (e.g.,porous ceramics), a thermally-conductive material (e.g., copper), anintumescent material, or any combination thereof.

FIG. 2C illustrates an exploded view of an embodiment of a battery pack200 according to the present technology. The battery pack may includesimilar components as previously discussed with regard to FIG. 2A, whileillustrating an additional arrangement of the battery cells 202. In someembodiments as illustrated, battery cells 202 may be positioned withinthe battery pack having the terminals 234 facing down. The terminals maybe located on a similar surface of the battery cells 202 as the vent, ormay be positioned on an opposite or adjacent surface of the batterycells as the vent.

FIG. 2D is an exploded view illustrating an exemplary construction ofbattery pack 200 in accordance with some embodiments. In the example ofFIG. 2D, jackets 242 in battery pack 200 encloses battery cells 202,further organizing battery cells into battery cell compartments. Thebattery pack 200 includes a jacket 242 enclosing one or more batterycells 202 disposed within each battery cell compartment 232. Jacket 242optionally includes apertures configured to expose terminals 234 of theone or more battery cells 202. Optionally, an electrically-insulatingmember 240 is disposed over the side of the battery cell 202 havingterminals 234. Jacket 242 optionally provides an opening configured toreceive battery cells 202. In FIG. 2D, the jacket 242 is depicted asenclosing two battery cells 202. However, this depiction is not intendedas limiting. The jacket 242 may enclose any number of battery cells 202.In some embodiments, the jacket 242 includes steel (e.g., 304, 316,1018, 4140, etc.).

FIG. 2E is an exploded view illustrating an exemplary construction ofbattery pack 200 in accordance with some embodiments. In the example ofFIG. 2E, sleeves 244 in battery pack 200 cover battery cells 202.Battery pack 200 includes a sleeve 244 covering one or more batterycells 202 disposed within each battery cell compartment 232. Sleeve 244has a first portion 246 and a second portion 248. The first portion 246covers the battery cells 202 along first sides having terminals 234disposed therein. The first portion 246 has apertures configured toexpose terminals 234 of the battery cells 202. The second portion 248covers second sides of the battery cells 202. The second sides areadjacent the first sides and may be perpendicular thereto. In FIG. 2E,the sleeve 244 is depicted as enclosing two battery cells 202. However,this depiction is not intended as limiting. The sleeve 244 may encloseany number of battery cells 202. In some embodiments, the sleeve 244includes steel (e.g., 304, 316, 1018, 4140, etc.). Optionally, anelectrically-insulating member 240 is disposed over the side of thebattery cell 202 having terminals 234.

FIG. 2F is an exploded view illustrating an exemplary construction ofbattery pack 200 in accordance with some embodiments. In the example ofFIG. 2F, longitudinal member 218 is a tubular structure. Furthermore,battery pack 200 includes base panel 236 and a cover panel 238. The basepanel 236 has openings configured to expose cell vents of the batterycell 202. The cover panel 238 has apertures configured to exposeterminals 234 of the battery cell 202 in a first orientation, and maynot include apertures in a second orientation where terminals 234 are onan opposite surface of the battery cells 202 where they may face basepanel 236. Optionally, an electrically-insulating member 240 is disposedover the side of the battery cell 202 having terminals 234. Inembodiments, the longitudinal member 218 divides the lateral member 224,the first end-member 204, and the second end-member 206 into separateportions. Such division partitions the perimeter 216 into a plurality ofconduits 250. Portions of the lateral member 224 may function asbulkheads within the plurality of conduits 250. In FIG. 2F, thelongitudinal member 218 divides the lateral member 224, the firstend-member 204, and the second end-member 206 into two conduits 250.However, this depiction is not intended as limiting. Multiplelongitudinal members 218 may be incorporated into the battery pack 200to define any number of conduits 250

Now referring to FIG. 3A, a perspective view is presented of a batterypack 300 having structural members that provide thermal management,according to some embodiments. FIG. 3B provides an exploded view of thebattery pack 300 illustrated in FIG. 3A. The battery pack 300 includes atubular structure 302, which in certain variations, may include aplurality of tubular structures 302 disposed side-by-side. FIG. 3Adepicts a specific variation where two tubular structures 302 aredisposed side-by-side. However, this depiction is not intended aslimiting. The tubular structure 302 may be aligned parallel to alongitudinal axis 304 of the battery pack 300. Each tubular structure302 includes a base member 306 having a bottom wall 308 extending from afirst side wall 310 to a second side wall 311. In some embodiments, suchas that shown in FIGS. 3A and 3B, an exterior-facing side wall 312 ofthe base member 306 includes a side beam 314.

Each tubular structure 302 also includes a cover member 316 coupled tothe base member 306 so as to define a channel 318 therebetween. Thechannel 318 may have a cross-section 320 of any type, including acircular cross-section, an elliptical cross-section, a hexagonalcross-section, a square cross-section, and a rectangular cross-section.The cover member 316 has apertures configured to expose terminals of thebattery cells. Each tubular structure 302 additionally includes alateral member 322 disposed within the channel 318 to divide the channel318 into a plurality of battery cell compartments 324. The lateralmember 322 may serve as a bulkhead within the channel 318. In someembodiments, such as that shown in FIGS. 3A and 3B, the plurality oftubular structures 302 include a plurality of lateral members 322 withineach channel 318.

It will be appreciated that any number of lateral members 322 may bedisposed within the channel 318. Moreover, the lateral members 322 maybe spaced so as to partition any combination of volumetric shapestherein. In this manner, the plurality of battery cell compartments 324can be configured to have any number and combination of shapes withinthe channel 318. The plurality of battery cell compartments 324 may bedifferent for each channel 318. In some embodiments, each of theplurality of battery cell compartments 324 is configured to contain twobattery cells therein. In some embodiments, the plurality of batterycell compartments 324 is configured such that battery cells disposedtherein have terminals aligned parallel to the lateral member 322.

A first end-member 326 is disposed at a first end 352 of the channel318. Similarly, a second end-member 327 is disposed at a second end 353of the channel 318. The end-members 326, 327 are operable to applypressure longitudinally against battery cells and lateral members 322disposed within the channel 318. In some embodiments, at least one ofthe base member 306 and the cover member 316 are configured to be intension when the plurality of battery cell compartments 324 contains arow of battery cells extending from the first end-member 326 to thesecond end-member 327. This tension predisposes the end-members 326, 327to compress battery cells within the plurality of battery cellcompartments 324 (i.e., longitudinally, laterally, vertically, or acombination thereof). Such compression may reduce swelling of batterycells within the channel 318 during operation (e.g., during charging,discharging, etc.) Reduced swelling may improve performance, lifetime,or both, of battery cells utilized by the battery pack 300 to store anddeliver electrical power.

In embodiments having the plurality of tubular structures disposedside-by-side, the battery pack 300 also includes a union member 328disposed along a seam between adjacent tubular structures 302 andcoupled to the adjacent tubular structures 302. Such coupling mayinvolve any component of the tubular structure 302 (e.g., the basemember 306, the cover member 316, etc.) Non-limiting examples of theunion member 328 include rods, pipes, beams, strips, plates, brackets,bars, trusses, wire, and cable. Other types of union members 328 arepossible. Coupling of the union member 328 to the adjacent tubularstructures 302 may involve welds, brazes, adhesives (e.g. epoxies,cements, etc.), fasteners (e.g., pins, bolts, rivets, etc.), or somecombination thereof. In some embodiments, such as that shown in FIGS. 3Aand 3B, the union member 328 is a strip disposed along the seam. Thestrip may be welded to the adjacent tubular structures 302.

One or more battery cells 330 may be disposed within the channel 318 toyield the battery pack 300. In some variations, the battery cells 330have terminals 332 on a side different than that of a cell vent (e.g.,an opposite side, adjacent side, top side, etc.). In some variations,the battery cells 330 have terminals 332 on a similar surface as a cellvent. In some variations, the base member 306 may include a plurality ofopenings 334 configured to expose cell vents of the battery cells 330.In some variations, an electrically-insulating member 336 is disposed ona side of the battery cells 330 having terminals 332.

In some embodiments, the battery cells 330 occupy greater than 84% of avolume within the channel 318. In some embodiments, the battery cells330 occupy greater than 86% of the volume within the channel 318. Insome embodiments, the battery cells 330 occupy greater than 88% of thevolume within the channel 318. In some embodiments, the battery cells330 occupy greater than 90% of the volume within the channel 318. Insome embodiments, the battery cells 330 occupy greater than 92% of thevolume within the channel 318. In some embodiments, the battery cells330 occupy greater than 96% of the volume within the channel 318. Insome embodiments, the battery cells 330 occupy greater than 98% of thevolume within the channel 318.

In general, the tubular structure 302 stiffens the battery pack 300longitudinally while providing a thermal functionality. Stiffening ofthe battery pack 300 improves resistance to loads, e.g., vertical loadsperpendicular to the base member 306 or the cover member 316. Thisimproved resistance allows the battery pack 300 to incorporate longerrows of battery cells 330 than those associated with conventionalbattery packs. In some embodiments, stiffness of the battery pack 300may be modified by altering a longitudinal tension of the base member306, the cover member 316, or both.

The thermal functionality of the tubular structure 302 is aided by thelateral member 322, which segregates battery cells 330 within thetubular conduit 302. Such segregation produces the plurality of batterycell compartments 324. The plurality of battery cell compartments 324isolates potential heat sources within controlled volumes for improvedthermal management. These volumes are bounded by walls associated withindividual battery cell compartments 324 (i.e., the lateral members 322and portions of the base member 306 and the cover member 316). In someinstances, the walls may include coatings or linings ofthermally-insulating material (e.g., porous ceramics),thermally-conductive material (e.g., copper), intumescent material, orany combination thereof. In some embodiments, the walls may bethermally-coupled with a heat exchanger.

In some embodiments, the battery pack 300 includes a battery cell 330disposed within at least one battery cell compartment 324. The batterycell 330 may have terminals on a side different than that of a cell vent(e.g., an opposite side, adjacent side, top side, etc.). The batterycell 330 may also have an electrically-insulating member 336 disposed onthe side of the battery cell 330 having terminals 332. In someinstances, the battery cell 330 occupies at least 90% of a volume of abattery cell compartment 324. In some instances, the battery cell 330occupies at least 92% of a volume of a battery cell compartment 324. Insome instances, the battery cell 330 occupies at least 94% of a volumeof a battery cell compartment 324. In some instances, the battery cell330 occupies at least 96% of a volume of a battery cell compartment 324.In some instances, the battery cell 330 occupies at least 98% of avolume of a battery cell compartment 324.

In some embodiments, the battery pack 300 includes two or more batterycells 330 disposed within at least one battery cell compartment of theplurality of battery cell compartments 324. A thermal divider may bedisposed between adjacent battery cells 330. The thermal divider may bea thermally-insulating material (e.g., porous ceramics), athermally-conductive material (e.g., copper), an intumescent material,or any combination thereof. In some instances, the battery cells 330 mayeach have terminals on a side opposite that of a cell vent. In someinstances, the electrically-insulating member 336 is disposed on theside of each battery cell 320 having terminals 332.

Materials for components of the battery pack 300 may be selected bythose skilled in the art based on considerations of yield strength,elastic modulus, thermal conductivity, and melting point. Otherconsiderations are possible.

In some embodiments, at least one of the base member 306, the covermember 316, the lateral member 322, the first end-member 326, and thesecond end-member 327 comprise a material having a yield strengthgreater than 250 MPa. In some embodiments, at least one of the basemember 306, the cover member 316, the lateral member 322, the firstend-member 326, and the second end-member 327 comprise a material havinga yield strength greater than 275 MPa. In some embodiments, at least oneof the base member 306, the cover member 316, the lateral member 322,the first end-member 326, and the second end-member 327 comprise amaterial having a yield strength greater than 300 MPa. In someembodiments, at least one of the base member 306, the cover member 316,the lateral member 322, the first end-member 326, and the secondend-member 327 comprise a material having a yield strength greater than325 MPa. In some embodiments, at least one of the base member 306, thecover member 316, the lateral member 322, the first end-member 326, andthe second end-member 327 comprise a material having a yield strengthgreater than 350 MPa. In some embodiments, at least one of the basemember 306, the cover member 316, the lateral member 322, the firstend-member 326, and the second end-member 327 comprise a material havinga yield strength greater than 375 MPa.

In some embodiments, at least one of the base member 306, the covermember 316, the lateral member 322, the first end-member 326, and thesecond end-member 327 comprise a material having an elastic modulusgreater than 65 GPa. In some embodiments, at least one of the basemember 306, the cover member 316, the lateral member 322, the firstend-member 326, and the second end-member 327 comprise a material havingan elastic modulus greater than 80 GPa. In some embodiments, at leastone of the base member 306, the cover member 316, the lateral member322, the first end-member 326, and the second end-member 327 comprise amaterial having an elastic modulus greater than 95 GPa. In someembodiments, at least one of the base member 306, the cover member 316,the lateral member 322, the first end-member 326, and the secondend-member 327 comprise a material having an elastic modulus greaterthan 110 GPa.

In some embodiments, at least one of the base member 306, the covermember 316, the lateral member 322, the first end-member 326, and thesecond end-member 327 comprise aluminum or an aluminum alloy (e.g.,2024, 6061, 7075, etc.). In other embodiments, at least one of the basemember 306, the cover member 316, the lateral member 322, the firstend-member 326, and the second end-member 327 comprise steel (e.g., 304,316, 1018, 4140, etc.). In still other embodiments, at least one of thebase member 306, the cover member 316, the lateral member 322, the firstend-member 326, and the second end-member 327 comprise titanium or atitanium alloy (e.g., Grade 1, Grade 2, Grade 5, Grade 23, etc.).

In some embodiments, at least one of the base member 306, the covermember 316, and the lateral member 322 comprise a material having athermal conductivity greater than 10 μm/m° C. In some embodiments atleast one of the base member 306, the cover member 316, and the lateralmember 322 comprise a material having a melting point greater than 550°C. In some embodiments, at least one of the base member 306, the covermember 316, and the lateral member 322 comprise steel (e.g., 304, 316,1018, 4140, etc.). In still other embodiments, at least one of the basemember 306, the cover member 316, and the lateral member 322 comprisetitanium or a titanium alloy (e.g., Grade 1, Grade 2, Grade 5, Grade 23,etc.).

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the describedembodiments. However, it will be apparent to one skilled in the art thatthe specific details are not required in order to practice the describedembodiments. Thus, the foregoing descriptions of the specificembodiments described herein are presented for purposes of illustrationand description. They are not targeted to be exhaustive or to limit theembodiments to the precise forms disclosed. It will be apparent to oneof ordinary skill in the art that many modifications and variations arepossible in view of the above teachings.

What is claimed is:
 1. A battery pack comprising: an enclosure having atleast four sidewalls connected to a base; a plurality of cells arrangedin one or more rows and disposed on the base, with each cell of theplurality of cells having a large wall surface and a small wall surface,a surface area of the small wall surface being less that a surface areaof the large wall surface; and wherein, for each row of the one or morerows, each of the plurality of cells are arranged such their large wallsurfaces are parallel to each other.
 2. The battery pack of claim 1,wherein two sidewalls of the at least four sidewalls are end plates thatare arranged parallel to the large wall surfaces with one of the twosidewalls being adaptable to apply compressive force to the plurality ofcells.
 3. The battery pack of claim 1, wherein the at least foursidewalls are mechanically attached or welded to the base.
 4. Thebattery pack of claim 1, wherein the battery pack is thermally coupledto a heat exchanger.
 5. The battery pack of claim 1, wherein at least 84percent of a volume of the battery pack is occupied by cells.
 6. Thebattery pack of claim 1, wherein each row of the one or more rows has asame number of cells.
 7. The battery pack of claim 1, wherein thebattery pack has at least two rows and each row is separated from anadjacent row by a divider.
 8. The battery pack of claim 1, wherein twoother sidewalls of the at least four sidewalls are arranged oppositeeach other along a plane of the small wall surface to confine to theplurality of cells.
 9. A battery pack comprising: an enclosure having atleast four sidewalls attached to a base; wherein a first sidewall of theat least four sidewalls is arranged to apply a compressive load to aplurality of cells.
 10. The battery pack of claim 9, wherein the atleast four sidewalls are welded to the base.
 11. The battery pack ofclaim 9, wherein the battery pack is thermally coupled to a heatexchanger.
 12. The battery pack of claim 9, wherein at least 84 percentof a volume of the battery pack is occupied by cells.
 13. The batterypack of claim 9, wherein the cells are arranged in a plurality of rowsand each row of the plurality of rows has a same number of cells. 14.The battery pack of claim 9, wherein the battery pack has at least tworows and each row is separated from an adjacent row by a divider. 15.The battery pack of claim 9, wherein two other sidewalls of the at leastfour sidewalls are arranged opposite each to confine to the plurality ofcells.
 16. A method for producing a battery pack, the method comprising:forming an enclosure that includes a base and at least four sidewalls,wherein at least one sidewall of the at least four sidewalls ismechanically attached to the base; providing a plurality of cells eachhaving a large wall surface and a small wall surface, wherein a surfacearea of the small wall surface is less than a surface area of the largewall surface; arranging the plurality of cells on the base such that thelarge wall surfaces are parallel to each other; and compressing theplurality of cells between at least two of the at least four sidewalls,the plurality of cells compressed in a direction perpendicular to thelarge wall surfaces.
 17. The method of claim 16, further comprisingforming the enclosure and arranging the plurality of cells on the baseof the enclosure such that at least 84% of a volume of the battery packis occupied by the plurality of cells.
 18. The method of claim 16,wherein the at least four sidewalls are welded to the base.
 19. Themethod of claim 16, wherein the battery pack is thermally coupled to aheat exchanger.
 20. The method of claim 16, wherein at least 84 percentof a volume of the battery pack is occupied by cells.